The study of ballistics involves the applied science as directed to the shape and motion of a projectile, not only in the bore of a gun, but also in flight and after it has impacted on a target.
Modern projectiles or bullets for small arms ammunition, i.e. 0.20 mm and smaller, are made exactly to size, with only the slightest manufacturing tolerances permitted. Lead bullets are made of a hardened alloy, and are shaped cold in dies from extruded wire of the proper size. The bullets are jacketed with a hard metal with the jackets being stamped from sheet stock, and drawn in dies to the proper shape and thickness. A lead slug is then inserted in the jacket and the whole is assembled in a press. A hard surfaced bullet of this type permits the use of a shallow rifling with a depth of 0.004 inch being common with stripping or fouling of the grooves by bullet metal being reduced, especially at high bore velocities.
A bullet may be intended either to expend its kinetic energy on the target, or to perforate and pass through with considerable remaining energy. Increasing the velocity offers an attractive method of increasing the available kinetic energy. Permissible pressure in the barrel of the gun, however, is limited, and substantial increases in velocity are most often obtained by reducing the weight of the bullet which reduces its capacity to maintain flight against air resistance and the target. Hence, high velocity bullets are more effective at the shorter ranges, while heavier, slower bullets have a greater total range and penetration.
Expansive bullets tend to deform and expend a maximum of their energy on the target. They expand upon contact with living tissue and produce great internal damage. All soft bullts and soft-nose, split-nose or hollow-point jacketed bullets are of this type.
In modern big game hunting, a need exists for nonexpansive bullets and increased bullet stability, thereby makingtthem capable of penetrating straighter and deeper than other heavier bullets of the same caliber. These bullets should have a good ballistic shape, uniform weight and symmetry for true flight.